Great question Olive. In the case of Unknown Moore, it looks like the merge has already taken place.
In the future when you get a merge notification and the other profile manager has approved, you click the "merge" button and you will be presented with both profiles one on the left and one on the right. You always want to merge into the correctly spelled surname, and if both are the same then the one with the lower number.
Go through the profile data and select the correct birth place, location, dates, etc. Remember, one profile may have the better birth location and one the better death location. Select the best data based on the sources.
Then in the bio section, merge the two together. If you have two == Biography == sections, delete one section header and move the two sets of biography data together.
You might end up with:
== Biography ==
John was born in 1774. His parents were Nathan and Mary Burns.
== Biography ==
John was born in 1774 in Virginia.
You would want to merge that into:
== Biography ==
John was born in 1774 in Virginia to parents Nathan and Mary Burns.
I hope this helps, please let us know if you have any other questions and be sure to read the help pages on merges:
https://www.wikitree.com/wiki/Help:Merging
